Abstract: The present invention provides an injection syringe comprises a housing including a holder for containing a cartridge of medicine, a piston rod with a non-circular cross-section having an outer thread, a piston rod drive, a one way coupling having an annular ring of internal ratchet notches, which annular ring can be integral with the housing, and a pawl having at least a pair of resilient arms each having a free end.

Abstract: The present invention relates to syringes for apportioning set doses from an ampoule has a dose setting and injection mechanism comprising a dose setting member which may be moved in one direction to set a dose and in the opposite direction to inject the set dose. A piston advancing mechanism comprises a piston rod and a piston rod drive, and the dose setting and injection mechanism is coupled to the piston advancing mechanism through a unidirectional coupling transmitting only movement of the dose setting member in the dose injecting direction to the piston rod drive. Operation of an air shot button enables influence on the piston advancing mechanism to advance the piston to expel an adjustable fixed volume. The air shot button is either coupled to the piston rod drive through a unidirectional coupling through which the piston rod is advanced when the air shot button is pressed, or it moves the end stop for an injection button so that this button may be pressed beyond its normal depressed end position.

Abstract: A dose setting mechanism for a drug administration device and an injection syringe having such a dose setting mechanism are provided. The injection syringe has a housing accommodating an ampoule (3) containing medicine sufficient for a number of dosed injections, an injection press button (7), a piston rod (13) for co-operation with a piston in the ampoule (3) when injecting, and a dose setting mechanism comprising a rotatable dose setting element (5) interconnected with the press button. The dose setting mechanism further comprises a dose administration wheel (11) connected with the piston rod (13) and a coupling ring (12) connected with the dose setting element (5) and the press button (7).

Abstract: An injection syringe comprises a housing (1), a piston rod (6) with a non-circular cross-section and an outer thread (7), a piston rod drive which includes a piston rod guide (85) mating with the cross-section of the piston rod (6), and a nut (4) which is not axially displaceable and which mates with the thread (7) of the piston rod (6) to form a self-locking thread connection. Rotation of a dose setting element (81) causes an injection button to be screwed out to project from the housing (1). When the injection button (88) is pushed axially, such axial movement is transformed, by way of the threaded coupling, into a rotation of one of the piston drive elements (85) relative to the other one (4). A unidirectional coupling between the nut member (4) and the piston rod guide (85) allows rotation in one direction by which the piston rod (6) is transported in a distal direction.

Abstract: The present invention relates to injection syringes comprising a housing accommodating an ampoule containing medicine sufficient for a number of dosed injections. The syringe has a dose setting mechanism by which doses may be set by rotating a dose setting element relative to the housing and the dose set is indicated on a scale. The scale is formed as a clock dial having a first part secured to the housing and a second part which is rotatable relative to the first part and which is coupled to the dose setting element, one of parts carries the scale and the other carries an indicating member indicating a point on the scale. The angular distance between the divisions of the scale corresponds to the minute divisions on an ordinary clock. Holes are provided along the scale which holes can receive a pin forming a stop which cannot be passed by the indicating member.